1. Field of the Invention
The present invention relates to desensitizer compositions. In more detail, the present invention relates to desensitizer compositions which decrease or eliminate the function of developers which cause coloration when contacted with substantially colorless color formers.
2. Description of the Prior Art
It is well known that color images are formed by the contact between color formers which are substantially colorless organic compound and developers. For instance, these color forming reactions are utilized in the recording materials described in U.S. Pat. Nos. 2,505,470; 2,505,489; 2,548,366; and 2,550,471, the recording materials described in U.S. Pat. Nos. 2,712,507; 2,730,457; and 3,293,060, the recording materials described in U.S. patent application Ser. No. 40,732 filed May 26, 1970 and British Pat. No. 825,354, and other recording materials such as for spirit printing, for stencil printing, in automatic vending systems, in the fingerprinting system and in the letter writing systems, etc.
In these recording materials, it is preferred for efficiency and economy to prevent the color-forming reaction on parts where formation of color images is not required by some means, because the color former and the developer form a color if they contact each other. Hitherto, desensitizers have been used for this purpose. For example, desensitizers as described in U.S. Pat. No. 2,777,780 (primary alkyl amines having a high molecular weight such as dodecylamine, quaternary ammonium salts such as dodecyl-trimethylammonium chloride, and alkyl or arylamine acetates), Japanese Patent Publication No. 29546/1971 (monoalkylamines, aralkylamines or tertiary amines in which ethanolamines chemically combine with ethyleneoxide groups), Japanese Patent Publication No. 35697/1971 (precondensates of urea resins), and others (secondary alkylamines such as didodecylamine, tertiary amines such as triethylamine, primary amines such as aniline, aralkyl amines such as benzylamine and polyhydroxyl compounds such as polyethylene glycol and glycerine, etc.) are known.
However, these desensitizers have disadvantages in that they have an insufficient desensitizing function or in that a practical effect is not obtained, even when they have a sufficient desensitizing function, if they are not used in a sufficient amount. Thus, with certain desensitizers, coloring can occur even if the desensitizers are used in a large amount. With other desensitizers, coloration can occur if the desensitizers are not used in a large amount. Particularly, these disadvantages become greater with the improvements made in color formers and developers.
For example, from a practical standpoint it is difficult to desensitize color formers having a fluoran ring as compared with Crystal Violet lactone etc. Further, these desensitizers barely show any desensitizing function for developers such as phenol resins and metal salts of aromatic carboxylic acids. Consequently, the advantageous properties of these developers (e.g. a property that the color image formed by using these developers does not disappear when contacted with water) cannot be utilized effectively. Another defect of these prior art desensitizers is that the undesensitized parts of the developers color with the lapse of time (the so-called generation of fog) when the desensitized developers are brought into contact with an encapsulated color former solution.
Further, the prior desensitizers yellow on the developers or they have the disadvantage that it is difficult to increase the coating (printing) speed because of a low drying rate, since they must be used in a large amount.
Accordingly, an object of the present invention is to provide desensitizer compositions having a high desensitizing function.
Another object of the present invention is to provide desensitizer compositions having a good coating tendency which can be used whether they are in an aqueous state or in an oily state.
A further object of the present invention is to provide desensitizer compositions which do not adversely influence color formers, developers and systems containing color formers and developers.